1. Field of the Invention
The present invention relates to organic fluids, and more particularly to organic fluids for use as the working fluid in high-temperature Organic Rankine Cycle (ORC) applications and as the heat transfer fluid in heat transfer cycles for a range of low and high temperatures, and a power plant using such organic fluids.
2. Background
High-temperature organic working fluids have been introduced as the working fluids in power plants and as working; and heat transfer intermediates in order to overcome the shortcomings of the use of the water steam medium used for heat transfer or for waste heat recovery and power generation. Heat-energy converters, based on the thermodynamic Organic Rankine Cycle, or similar beat-energy transfer systems, are useful in heat recovery and power generation in particular in remote locations, where the heat is derived from various sources, such as gas turbine exhaust gases, combustion of conventional fuels, combustion of biomass fuels, geothermal sources, solar heat collects and waste heat in power plants and other industrial processes, for the purpose of producing electrical power in the range of from a hundred or mace Watts (W) and up to a few of tens Megawatts (MW). Organic fluids sustainable at temperatures as high as about 350° C. are advantageous over water-steam, and can be successfully utilized in power generation cycles even at low condensing temperatures and high turbine expansion ratios where the use of steam may be limited due to formation of liquid droplets at the turbine outlet due to the expansion of the steam which may cause erosion to the turbine blades. Because of the nature of the organic fluids they become superheated (or dry) in the expansion process a characteristic which prevents the formation of liquid droplets as is the case with steam. Organic fluids and their derivatives operable under a range of relatively low temperatures normally up to about 20000 are CFCs, Freon, butane including n-butane and iso-butane, and pentane, also including the n-pentane and iso-pentane isomers. For applications where higher operating temperatures are required a transition was required to aromatic hydrocarbons, alkylated aromatic hydrocarbons, fluorinated hydrocarbons such as F75 and F43 and silicone based oils. Examples for alkylated aromatic hydrocarbons are commercial Dowtherm J, which is a mixture of isomers of alkylated aromatic hydrocarbon manufactured by the Dow Chemical Company and Therminol LT, an alkyl substituted aromatic hydrocarbon, manufactured by the Solutia Inc.